The invention relates to an exhaust gas turbocharger turbine for an internal combustion engine with an axially slidable control sleeve, which include guide vanes and is supported in an annular gap between the turbine housing and an annular guide structure and with an annular gas flow passage disposed in the turbine housing and leading to the turbine wheel.
DE 47 32 400 Cl discloses an exhaust gas turbocharger turbine for an internal combustion engine with an adjustable flow guide mechanism. It includes an annular control sleeve, which is axially movable for blocking the inlet flow cross-section between a guide channel and a turbine wheel. In this way, a throttling cross-section forming a brake gap for a motor brake can be provided.
However, because of its design, turbulence is generated within the housing of this exhaust gas turbocharger turbine which leads to a relatively low efficiency of the whole exhaust gas turbocharger turbine. In addition, the arrangement described in this reference will have gap losses caused by the escape of exhaust gases, which further decrease the turbine efficiency.
U.S. Pat. No. 5,452,986 discloses a diffuser structure for a turbo machine having a housing with a control arrangement including an axially movable control ring. The control ring includes flow guides vanes and is supported in an annular space formed in the housing. The flow guide vanes extend through openings in a guide ring into the flow path of the gas and are axially movable with the control ring whereby they are rotated for varying the stagger angle of the vanes depending on how far they are projecting into the flow passage.
This arrangement, however, has the disadvantage that, when the guide vanes extend into the flow passage, there is a gap between the control ring and the guide ring at the openings of the guide ring. As a result, insufficient sealing is achieved when the guide vanes are fully retracted from the annular flow passage. As a result, turbulence can occur in the area of the openings.
It is the object of the present invention to provide an exhaust gas turbocharger turbine for an internal combustion engine with improved flow conditions within the turbine housing and relatively low gap losses.